It is known to provide a piece of machinery with an automatic lubricant dispenser that is pressurized to force a fluent lubricant, normally an oil or grease, along a conduit into a part, typically a bearing, of the machine. In order to avoid having to provide a pump it has been suggested to provide a gas-generating cell which pressurizes the lubricant by means of a chemical reaction that can be initiated by the user when the dispenser is connected to the machine, and that generates sufficient gas to deplete the entire supply of lubricant in the dispenser.
In commonly owned U.S. Pat. Nos. 5,386,883 and 5,409,084 such a dispenser is described which has a vessel adapted to hold a supply Of a fluent lubricant and having one side formed with an outlet adapted to be connected via a conduit to a machine to be lubricated and another open side and a cover engaged over the other side and fitted with a cap fittable snugly like a piston in the vessel and forming with the cover a substantially closed chamber holding a supply of a reactive liquid. The cover is formed with a seat opening into the chamber. A gas-generating cartridge fits into the seat and has an element capable of reacting with the liquid and forming a gas. A removable partition closes the seat and segregates it from the liquid-holding chamber. The cartridge is constructed so as to remove the partition and contact the element with the liquid for generating gas in the chamber and forcing the cap like a piston away from the cover into the vessel to pressurize the fluent lubricant therein.
In all of these systems the activation is nonreversible, that is once the partition is removed or destroyed, the gas-generating reaction is started and cannot be stopped. Thus if the machine is to be taken out of service for a long time, it becomes necessary to replace the lubricant dispenser before restarting the machine, since the gas will all have leaked away. Similarly even if the machine is sitting idle, the automatic lubricant dispenser continues to toil away, periodically feeding new lubricant to the down machine, a clear waste. Finally the gas-type pressurizing cartridge is a disposal problem when depleted, and cannot be renewed or reused.